Week 7: Multiplication by 11
Beginner Level • Estimated: 45 minutes
Multiplication by 11
The Magical ×11 Trick!
Get ready to learn one of the most amazing Vedic Mathematics tricks! Today you'll discover how to multiply any number by 11 instantly in your head! 🎩✨
Why This Trick is Magical
Lightning Fast
Solve in seconds, not minutes
No Calculator
Pure mental math power
Impressive
Amaze friends and family
Magic Secret
The trick works because 11 = 10 + 1. We're using the distributive property in a clever way!
The Basic Magic Trick
For 2-digit numbers: "Add digits, put sum in middle"
"For AB × 11, write A, (A+B), B"
Step-by-Step Magic:
Write the first digit: 3
Add the digits: 3 + 5 = 8
Write the last digit: 5
Magical Result: 35 × 11 = 385
Traditional Method:
35 × 10 = 350
35 × 1 = 35
350 + 35 = 385
3 steps with carrying
Magic Trick with Carrying
When digits add to 10 or more
"If sum is 10+, write units digit, carry tens to left"
Step-by-Step with Carry:
Add digits: 5 + 7 = 12
Write units digit (2) in middle
Carry tens digit (1) to left
Left digit becomes: 5 + 1 = 6
Magical Result: 57 × 11 = 627
Magic Rule:
If sum ≥ 10:
• Write units digit
• Carry 1 to left
• Add carry to left digit
68 × 11 = ?
Click to solve
79 × 11 = ?
Click to solve
94 × 11 = ?
Click to solve
Magic for 3-Digit Numbers
For ABC × 11: "A, (A+B), (B+C), C"
"Work from right to left, add adjacent digits"
Step-by-Step 3-digit Magic:
Start with right digit: 3
Add middle digits: 2 + 3 = 5
Add left digits: 1 + 2 = 3
End with left digit: 1
Magical Result: 123 × 11 = 1353
Pattern:
For ABC × 11:
A (A+B) (B+C) C
Read from right to left!
Magic Practice Arena
Test Your ×11 Magic Powers
72 × 11 = ?
2-digit, no carry
89 × 11 = ?
2-digit, with carry
345 × 11 = ?
3-digit challenge
Magic in Real Life
Shopping with ×11 Magic
Shopping Scenario:
You buy 11 notebooks. Each costs ₹45. How much total?
Problem: 45 × 11
Add digits: 4 + 5 = 9
Write: 4, 9, 5
Instant Answer: ₹495
Group Calculation:
11 friends want pizza. Each pizza has 8 slices. Total slices?
Problem: 8 × 11
Think: 08 × 11
Add: 0+8=8, write: 0, 8, 8
Instant Answer: 88 slices
This Week's Magical Goals
- Multiply any 2-digit number by 11 instantly
- Handle carries when digits sum to 10+
- Multiply 3-digit numbers by 11 quickly
- Apply ×11 magic to real-world problems
- Amaze others with your mental math speed
Complete this lesson to earn:
×11 Multiplication Wizard Badge
Unlock after completing Week 7
Magical Spell Summary
Today we learned the amazing multiplication by 11 trick:
- 2-digit numbers: Write first digit, sum of digits, last digit
- With carries: When sum ≥ 10, write units digit, carry 1 left
- 3-digit numbers: A, (A+B), (B+C), C (work right to left)
Pro Magic Tip
Practice this trick with random numbers throughout the day. The more you use it, the more magical it feels!